Intensity Modulated Radiation Therapy (IMRT) Target Volume and Dosimetric Planning in Treatment of Locally Advanced Non-small Cell Lung Cancer

ObjectiveTo assess elective nodal irradiation (ENI) and involved field irradiation (IFI) target volume and dosimetric distribution and to obtain the optional intensity modulated radiation therapy (IMRT) planning for locally advanced non-small cell lung cancer (LA-NSCLC). Methods Two different plannings: ENI and IFI were designed to assess the dosimetric distribution of target volume and normal tissues for 27 patients with LA-NSCLC confirmed through pathology. Dose volume histograms (DVHs), target volume conformal index (CI), tumor control probability (TCP), normal tissue irradiation dose and normal tissue complication probability (NTCP) were used to assess the IMRT planning. Results The maximum dose, minimum dose, average dose, CI, and TCP of GTV by IFI and ENI were 77.1 Gy vs. 73.9 Gy, 67.3 Gy vs. 63.6 Gy, 70.9 Gy vs. 67.1 Gy, 0.82 vs. 0.73, 96.7% vs. 93.1%, respectively (P<0.05). The average dose, total lung volume received radiation exceeding 20 Gy (V20) and NTCP of lung were 13.2 Gy vs. 16.0 Gy, 22.1% vs. 24.7%, 5.2% vs. 5.8%, respectively (P<0.05). The total esophagus volume received radiation exceeding 45 Gy (V45) by IFI and ENI were 16.3% vs. 21.7%, however the length of esophagus (total circumference) treated with greater than 45 Gy (LETT45), average dose of heart and the maximum dose of spinal cord had no different significantly between IFI and ENI respectively (P> 0.05). ConclusionTarget volume dosimetric distribution of IFI is significantly better than ENI. Therefore, we suggest IFI in patients with LA-NSCLC.